Posted on 01/08/2009 9:54:17 PM PST by SunkenCiv
Multiple comet impacts around 1500 years ago triggered a "dry fog" that plunged half the world into famine.
Historical records tell us that from the beginning of March 536 AD, a fog of dust blanketed the atmosphere for 18 months. During this time, "the sun gave no more light than the moon", global temperatures plummeted and crops failed, says Dallas Abbott of Columbia University's Lamont-Doherty Earth Observatory in New York...
Now Abbott and her team have found the first direct evidence that multiple impacts caused the haze. They found tiny balls of condensed rock vapour or "spherules" in debris inside Greenland ice cores dating back to early 536 AD. Though the spherules' chemistry suggests they did not belong to an impactor, they do point to terrestrial debris ejected into the atmosphere by an impact event, Abbott says. "This is the first concrete geological evidence for an impact at 536 AD," she says.
The fallout material was also laid down over several years, and some layers were particularly densely deposited. This suggests more than one impactor was involved -- probably a comet, because they tend to fragment on their way to Earth.
Abbott and her team have identified two possible underwater craters whose age ranges fit the global dimming event. The first appears to have formed when an object roughly 640 metres wide slammed into the Gulf of Carpentaria in Australia, and the other when a smaller object crashed into the North Sea near Norway.
Marine microfossils found with the impact spherules are also consistent with an ocean impact. "There's clearly stuff that has been transported a long distance," says Abbott, who presented the team's findings at the meeting of the American Geophysical Union in San Francisco last month.
(Excerpt) Read more at newscientist.com ...
Tree rings challenge historyMike Baillie, professor of palaeoecology at Queen's University in Belfast, UK, said it was very clear from the narrowness of growth rings in bog oaks and archaeological timbers that a great catastrophe struck the Earth in AD 540. He said mythical stories certainly seemed to point to a comet striking the Earth at about the right time. He said King Arthur died in this period and some stories talk about long arms in the sky delivering mighty blows. Professor Baillie said chemical analysis would be carried out on the tree rings to investigate the comet idea further. He hopes also to get access to ice cores to see if they record any interesting data that might support the comet theory.
by BBC News Online's Jonathan Amos
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Do you read New Scientist? I would occassionally peruse it in our physics library. It’s well put together, but always seemed uber political to me.
Tree rings challenge historyMike Baillie, professor of palaeoecology at Queen's University in Belfast, UK, said it was very clear from the narrowness of growth rings in bog oaks and archaeological timbers that a great catastrophe struck the Earth in AD 540. He said mythical stories certainly seemed to point to a comet striking the Earth at about the right time. He said King Arthur died in this period and some stories talk about long arms in the sky delivering mighty blows. Professor Baillie said chemical analysis would be carried out on the tree rings to investigate the comet idea further. He hopes also to get access to ice cores to see if they record any interesting data that might support the comet theory.
by BBC News Online's Jonathan Amos
Friday, September 8, 2000
I think I subscribed at one time, for a year, or some fraction of a year. They’ve had their heads up their keisters vis a vis “global warming”, but lots of mags do. There are those who rubbish it, but it probably should be a source to mine for GGG stories. I got this link from another FReeper. :’)
Ancient tree rings give climate clues
Wednesday, 28 March, 2001, 19:09 GMT 20:09 UK
http://news.bbc.co.uk/1/hi/sci/tech/1247636.stm
Mystery Of Infamous ‘New England Dark Day’ Solved By Tree Rings
http://www.sciencedaily.com/releases/2008/06/080606145620.htm
Tree-ring reconstructed megadroughts over North America since a.d. 1300
http://www.springerlink.com/content/5478q5t795671806/
Were the Dark Ages Triggered by Volcano-Related Climate Changes in the 6th Century?
(If so, was Krakatau volcano the culprit?)
by Ken Wohletz
Los Alamos National Laboratory
LA-UR 00-4608
Copyright © 2000 UC “With no supporting evidence for an impact-related event,........ Writings from China and Indonesia describe rare atmospheric phenomena that possibly point to a volcano in the Indonesian arc. Although radiocarbon dating of eruptions in that part of the world are spotty, there is strong bathymetric and volcanic evidence that Krakatau might have experienced a huge caldera eruption. Accordingly, I encouraged a scientific expedition to be led by Haraldur Sigurdsson to the area. The expedition found a thick pyroclastic deposit, bracketed by appropriate radiometric dates, that suggests such a caldera collapse of a Proto-Krakatau did occur perhaps in the 6th century. Bathymetry indicates a caldera some 40 to 60 km in diameter that, with collapse below sea level, could have formed the Sunda Straits, separating Java from Sumatra, as suggested by ancient Javanese historical writings”
Yes, its true! And... it is all Bush’s fault!!!
fascinating!
the fog sounds like houston
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